A retention-excretion model for americium in humans

Area of Science:

• Radiological science
• Biokinetics
• Human health risk assessment

Background:

• Understanding americium's biological behavior is crucial for assessing human health risks.
• Existing models for americium biokinetics have limitations in accurately predicting its long-term distribution and excretion.

Purpose of the Study:

• To develop and present a comprehensive biokinetic model for americium in humans.
• To analyze the time-dependent distribution and excretion of systemic americium in adults.
• To provide predictive models for americium absorption from the respiratory and gastrointestinal tracts.

Main Methods:

• Building upon previous biokinetic models for plutonium.
• Incorporating recent analyses and models of americium behavior in humans and animals.
• Developing a time-dependent model focusing on adult physiology, with considerations for age-related differences.

Main Results:

• The new model predicts similar whole-body americium retention to ICRP Publication No. 48 but less liver retention and greater skeletal retention after several years.
• Compared to the Durbin and Schmidt model, it shows similar liver retention, slightly less skeletal retention, and higher urinary excretion rates.
• Provides detailed predictions for americium absorption via inhalation and ingestion.

Conclusions:

• The developed biokinetic model offers a refined understanding of americium's behavior in the human body.
• It provides more accurate predictions for americium distribution, excretion, and retention, particularly in the liver and skeleton.
• This model can aid in improved human health risk assessments related to americium exposure.